Vane-type rotary air pumps



Allg. 17, 1965 G. H. BRlscoE 3,201,033

GGGGGGGGGGGGG OE United States Patent O This invention concerns improvements in vane-type rotary air pumps of the kind having a rotor and sliding vanes within that rotor, and is especially but not essentially directed to non-lubricated or dry pumps of this kind.

Air pumps of the kind referred to are in increasing dei mand for use in situations where noise above a certain level -is intolerable Ifor example in computing machines, but unfortunately the necessary running clearance between vane and rotor is inclined to induce a considerable clatter and this is particularly marked in dry pumps, where there is no film of oil to take up running clearance.

According to the invention I provide an air pump of the kind referred to characterised by the provision of means located within the rotor barrel whereby a force is applied to at least one of the major faces of the vane or vanes tending to press it against at least the other major face of the guide slot in which it operates.

In the preferred embodiment of the invention, a drilling led from the base of a preceding blade slot to the side of a following vane slot transmits oil pressure to the side of the following vane as the preceding vane is forced into its slot. This arrangement is particularly adapted for use in lubricating pumps with chordal vanes.

In operation the pumps tted with vane side thrust inducers are very noticeably quieter than similar pumps under similar duty not so fitted.

A preferred embodiment of the invention is illustrated in the accompanying drawing, which is a purely diagrammatic cross-section of a pump rotor taken at right angles to its axis of rotation.

Referring specifically to the drawing, a rotor 2, eccentrically operative within a cylindrical chamber 4, is provided with a plurality of vane slots 6 opening through the periphery of the rotor and having vanes 8 slidable in said 3,201,033 Patented Aug. 17, 1955 ICC slots with their outer edges in engagement with the peripheral wall of the chamber 4. The illustrated embodiment may be assumed to be in a lubricated pump having chordal vanes.

A bore 10 is drilled from the base of each guide slot 6 of a preceding vane 8 to the leading face of the guide slot 6 of the succeeding vane 8. The bores 10 constitute conduits from the bottom of each of the slots 6 yopening only into a major face of the respective succeeding slots 6 and define a closed communication therebetween. It will be seen that, as each vane 8 approaches top dead centre, it is forced down its guide slot 6 and thus causes a build up of oil pressure in the bore 10 in communication therewith, which pressure is applied to the leading face of the succeeding vane 8.

There may of course be several bores such as 10 within the length of each vane guide slot 6.

I claim:

In a vane-type rotary air pump the improvements comprising a rotor having peripheral slots, vanes slideable in said slots, and conduits from the bottom of each of said slots opening only into a major face of the respective succeeding slot and dening a closed communication therebetween, whereby movement of each vane within its slot produces a uid pressure within the conduit which is ap plied to a major face of the vane in the succeeding slot to press said succeeding vane against the face of the slot in which it operates.

References Cited bythe Examiner UNITED STATES PATENTS 1,058,496 4/13 Thompson 91-140 1,321,340 11/19 Stoke 230--152 2,189,969 2/40 Taglio 230-152 2,708,884 5/55 Deschamps 103--135 FORETGN PATENTS 605,006 11/34 Germany.

KARL J. ALBRECHT, Primary Examiner. JOSEPH H. BRANSON, IR., Examiner. 

